This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
Prismatic Triangular Background Design Mark II 5
Source GDJ
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Prismatic Groovy Concentric Background 2
Source GDJ
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
I love the movie Pineapple Express, and I’m also liking this Pineapple right here.
Source Audee Mirza
Looks as if it's spray painted on the wall. You can be sure that this pattern will seamlessly fill your backgrounds on web pages.
Source V. Hartikainen
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
From drawing in 'Musings in Maoriland', Thomas Bracken, 1890.
Source Firkin
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
A gray background pattern with a texture of textile. Suits perfectly for web design.
Source V. Hartikainen
A comeback for you: the popular Escheresque, now in black.
Source Patten
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by captenpub.
Source Firkin
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen